Blender is rendering an older version my project
This is because you have some sequencer strips in the VSE.

The Compositor and Sequence  settings are enabled by default, so if there is any data in the compositor or the sequencer blender will render from that instead of the scene.

From the wiki:


  If
  you are using the Compositor or Sequencer, you can tell Blender to
  process those effects instead of directly rendering the scene.


Disable Sequence in Render Settings > Post processing or remove the sequencer strips and it will render the scene instead:

version 2.8x